Electrophysiology and calcium imaging will be used to study olfactory receptor neuron (ORN) responsiveness in a novel tissue slice preparation. Three specific aims are delineated. In the first specific aim, the sensitivity, selectivity and adaptive properties of the ORNs will be studied using loose, perforated and whole cell patch recording. In the second aim, imaging of intracellular calcium will be used to determine whether odors elicit stereotypic patterns of neuronal activity in the epithelium, and whether these patterns correlate with the olfactory receptor expression zones of the olfactory epithelium. Finally, in the third specific aim experiments are proposed to study responsiveness of ORN expressing a specific receptor (P2) in a gene-targeted mouse co-expressing the marker protein taulacZ.